/Engine/Plugins/FX/Niagara/Source/NiagaraEditor/Public/ViewModels/NiagaraParameterPanelViewModel.h
Delegate to handle responses to external selection changes (e.g.TNiagaraSelectionchanges.)
typedef TMulticastDelegate_OneParam< void, const [UObject](API\Runtime\CoreUObject\UObject\UObject) * > FOnParameterPanelViewModelExternalSelectionChanged